I came across this: "if a tamable person doesn’t submit either to a mild training or to a harsh training or to a mild & harsh training, then the Tathagata doesn’t regard him as being worth speaking to or admonishing.
More famously this pattern is found in the Satipatthana sutta refrain. I wondered whether this pattern found in the suttas was merely a way to emphasise the completeness of the different approaches taken, rather than pointing at a third ‘hybrid’ approach.
Regarding the listing of mild, harsh, and mild & harsh training: by my reading of the sutta the third category (mild & harsh) is obviously a combination of gentle training (focusing on positive kamma and rewards) and harsh training (focusing on negative kamma and drawbacks). This is plainly stated in the text. We can’t, however, say that it is similarly stated so explicitly in the satipaṭṭhāna. Bhante Sujāto discusses the issue around p. 206 of his 2012 “A History of Mindfulness”, there he brings in some passages from other suttas to elucidate. Internal/external seems to be a kind of universalization based on the previous internal contemplation and external contemplation, seeing beyond the the difference between internal and external.
emphasise the completeness of the different approaches taken, rather than pointing at a third ‘hybrid’ approach.
an example of this is the 5 masterys of perception, as described in suttas such as SN 54.8 “the lamp”, and MN 152.
using the “completeness” interpretation, the 5 masteries can be interpreted to mean learning how to adjust our perception of any phenomena, whether pleasant, unpleasant, desirable, cruel, any unskillful perception of any type whatsoever, and replace it with a skillful perception that leads to skillful results such as disenchantment, dispassion, strengthening of virtue, concentration, wisdom, etc.
if we were to take it only literally as 5 types with those weird hybrids, then it’s not nearly as useful. i believe those weird hybrids that don’t quite make sense if you try to practice it literally, is a rhetorical device that’s easier to memorize in an oral tradition than the more precise but harder to memorize way i stated above.